config.toml: debuginfo option documentation is confusing

[RalfJung]

The current documentation for the debuginfo options looks like this:

# Whether or not debuginfo is emitted
#debuginfo = false

# Whether or not line number debug information is emitted
#debuginfo-lines = false

# Whether or not to only build debuginfo for the standard library if enabled.
# If enabled, this will not compile the compiler with debuginfo, just the
# standard library.
#debuginfo-only-std = false

# Enable debuginfo for the extended tools: cargo, rls, rustfmt
# Adding debuginfo makes them several times larger.
#debuginfo-tools = false

Now I am left wondering:

• If I want to have debuginfo for std and nothing else, I thought I had to just change debuginfo-only-std but that did not have any effect. So it seems I first have to enable debuginfo but then restrict it using only-std? That's surprising, and not documented.
• If I set debuginfo, debuginfo-only-std and debuginfo-tools, which things get debuginfo?
• If I set debuginfo = false and debuginfo-tools = true, do the tools get debuginfo?